Fuel processor for producing a hydrogen rich gas

ABSTRACT

An apparatus for converting hydrocarbon fuel to a hydrogen rich gas including a first heat exchanger for heating the hydrocarbon fuel, a first desulfurization reactor for reacting a heated hydrocarbon fuel to produce a substantially desulfurized hydrocarbon fuel, a manifold for mixing the substantially desulfurized hydrocarbon fuel with an oxygen containing gas to produce a fuel mixture, a second heat exchanger for heating the fuel mixture, an autothermal reactor including a catalyst for reacting the heated fuel mixture to produce a first hydrogen containing gaseous mixture, a second desulfurization reactor for producing a second hydrogen containing gaseous mixture that is substantially desulfurized, a water gas shift reactor for reacting the second hydrogen containing gaseous mixture to produce a third hydrogen containing gaseous mixture with a substantially decreased carbon monoxide content, and a selective oxidation reactor for reacting the third hydrogen containing gaseous mixture to produce the hydrogen rich gas.

The present application is a divisional application of U.S. Ser. No.10/006,879, filed Dec. 5, 2001, which claims priority from U.S.Provisional Patent Application No. 60/251,226, filed Dec. 5, 2000, thecomplete disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Fuel cells provide electricity from chemical oxidation-reductionreactions and possess significant advantages over other forms of powergeneration in terns of cleanliness and efficiency. Typically, fuel cellsemploy hydrogen as the fuel and oxygen as the oxidizing agent. The powergeneration is proportional to the consumption rate of the reactants.Thus, many types of fuels can be used; some of them hybrids with fossilfuels, but the ideal fuel is hydrogen. If the fuel is, for instance,hydrogen, then the combustion is very clean and, as a practical matter,only the water is left after the dissipation and/or consumption of theheat and the consumption of the electricity. Most readily availablefuels (e.g., natural gas, propane and gasoline) and even the less commonones (e.g., methanol and ethanol) include hydrogen in their molecularstructure. Some fuel cell implementations therefore employ a “fuelprocessor” that processes a particular fuel to produce a reformatestream used to fuel the fuel cell.

A significant disadvantage which inhibits the wider use of fuel cells isthe lack of a widespread hydrogen infrastructure. Hydrogen has arelatively low volumetric energy density and is more difficult to storeand transport than the hydrocarbon fuels currently used in most powergeneration systems. One way to overcome this difficulty is the use ofreformers to convert the hydrocarbons to a hydrogen rich gas streamwhich can be used as a feed for fuel cells.

Hydrocarbon-based fuels, such as natural gas, LPG, gasoline, and diesel,require conversion processes to be used as fuel sources for most fuelcells. Current art uses multi-step processes combining an initialconversion process with several clean-up processes. The initial processis most often steam reforming (SR), autothermal reforming (ATR),catalytic partial oxidation (CPOX), or non-catalytic partial oxidation(POX). The clean-up processes are usually comprised of a combination ofdesulfurization, high temperature water-gas shift, low temperaturewater-gas shift, selective CO oxidation, or selective CO methanation.Alternative processes include hydrogen selective membrane reactors andfilters.

Despite the above work, there remains a need for a simple unit forconverting a hydrocarbons fuel to a hydrogen rich gas stream for use inconjunction with a fuel cell.

SUMMARY OF THE INVENTION

The present invention is generally directed to an apparatus and methodfor converting hydrocarbon fuel into a hydrogen rich gas. In oneillustrative embodiment, the fuel processor of the present inventionincludes a heat exchanger for heating the hydrocarbon fuel feed prior toentering a desulfurization reactor. The substantially desulfurizedhydrocarbon fuel is then mixed in a manifold with an oxygen containinggas to produce a fuel mixture. This fuel mixture is then heated inanother heat exchanger before being fed to an autothermal reformingreactor. The resulting hydrogen containing gaseous mixture is then fedto a second desulfurization reactor before being fed to a water gasshift reactor which substantially decreases the carbon monoxide contentof the hydrogen containing gaseous mixture. Finally, a selectiveoxidation reactor can be utilized to produce the hydrogen rich gas.

In another illustrative embodiment, the method of the present inventioncan be utilized for converting hydrocarbon fuel into a hydrogen rich gasby first heating the hydrocarbon fuel to produce a heated hydrocarbonfuel before reacting the heated hydrocarbon fuel in the presence of acatalyst under desulfurization conditions to produce a substantiallydesulfurized hydrocarbon fuel. The fuel can then be mixed with an oxygencontaining gas to produce a fuel mixture. The fuel mixture is thenheated before reacting in the presence of a catalyst under autothermalreforming conditions to produce a hydrogen containing gaseous mixture.This mixture is then reacted in the presence of a catalyst underdesulfurization conditions to produce a substantially desulfurizedhydrogen containing gaseous mixture, which can be further reacted underwater gas shift reaction conditions to produce a hydrogen containinggaseous mixture with a carbon monoxide content less than 50 ppm.Finally, this hydrogen stream can be reacted in the presence of acatalyst under selective oxidation reaction conditions of to produce thehydrogen rich gas product.

BRIEF DESCRIPTION OF THE DRAWINGS

The description is presented with reference to the accompanying drawingsin which:

FIG. 1 depicts a simple process flow diagram for one illustrativeembodiment of the present invention.

FIG. 2 one embodiment of a fuel processor of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is generally directed to an apparatus forconverting hydrocarbon fuel into a hydrogen rich gas. In a preferredaspect, the apparatus and method described herein relate to a compactprocessor for producing a hydrogen rich gas stream from a hydrocarbonfuel for use in fuel cells. However, other possible uses arecontemplated for the apparatus and method described herein, includingany use wherein a hydrogen rich stream is desired. Accordingly, whilethe invention is described herein as being used in conjunction with afuel cell, the scope of the invention is not limited to such use.

Each of the illustrative embodiments of the present invention describe afuel processor or a process for using such a fuel processor with thehydrocarbon fuel feed being directed through the fuel processor. Thehydrocarbon fuel may be liquid or gas at ambient conditions. As usedherein the term “hydrocarbon” includes organic compounds having C—Hbonds which are capable of producing hydrogen from a partial oxidationor steam reforming reaction. The presence of atoms other than carbon andhydrogen in the molecular structure of the compound is not excluded.Thus, suitable fuels for use in the method and apparatus disclosedherein include, but are not limited to hydrocarbon fuels such as naturalgas, methane, ethane, propane, butane, naphtha, gasoline, and dieselfuel, and alcohols such as methanol, ethanol, propanol, and the like.

The fuel processor feeds include hydrocarbon fuel, oxygen, and water.The oxygen can be in the form of air, enriched air, or substantiallypure oxygen. The water can be introduced as a liquid or vapor. Thecomposition percentages of the feed components are determined by thedesired operating conditions, as discussed below.

The fuel processor effluent stream from of the present inventionincludes hydrogen and carbon dioxide and can also include some water,unconverted hydrocarbons, carbon monoxide, impurities (e.g. hydrogensulfide and ammonia) and inert components (e.g., nitrogen and argon,especially if air was a component of the feed stream).

FIG. 1 depicts a general process flow diagram illustrating the processsteps included in the illustrative embodiments of the present invention.One of skill in the art should appreciate that a certain amount ofprogressive order is needed in the flow of the reactants through thereactors disclosed herein.

Process step A is an autothermal reforming process in which tworeactions, partial oxidation (formula I, below) and optionally alsosteam reforming (formula II, below), are combined to convert the feedstream F into a synthesis gas containing hydrogen and carbon monoxide.Formulas I and II are exemplary reaction formulas wherein methane isconsidered as the hydrocarbon:CH₄+½ O₂→2H₂+CO  (I)CH₄+H₂O→3H₂+CO  (II)

The partial oxidation reaction occurs very quickly to the completeconversion of oxygen added and produces heat. The steam reformingreaction occurs slower and consumes heat. A higher concentration ofoxygen in the feed stream favors partial oxidation whereas a higherconcentration of water vapor favors steam reforming. Therefore, theratios of oxygen to hydrocarbon and water to hydrocarbon becomecharacterizing parameters. These ratios affect the operating temperatureand hydrogen yield.

The operating temperature of the autothermal reforming step can rangefrom about 550° C. to about 900° C., depending on the feed conditionsand the catalyst. The invention uses a catalyst bed of a partialoxidation catalyst with or without a steam reforming catalyst. Thecatalyst may be in any form including pellets, spheres, extrudate,monoliths, and the like. Partial oxidation catalysts should be wellknown to those with skill in the art and are often comprised of noblemetals such as platinum, palladium, rhodium, and/or ruthenium on analumina washcoat on a monolith, extrudate, pellet or other support.Non-noble metals such as nickel or cobalt have been used. Otherwashcoats such as titania, zirconia, silica, and magnesia have beencited in the literature. Many additional materials such as lanthanum,cerium, and potassium have been cited in the literature as “promoters”that improve the performance of the partial oxidation catalyst.

Steam reforming catalysts should be known to those with skill in the artand can include nickel with amounts of cobalt or a noble metal such asplatinum, palladium, rhodium, ruthenium, and/or iridium. The catalystcan be supported, for example, on magnesia, alumina, silica, zirconia,or magnesium aluminate, singly or in combination. Alternatively, thesteam reforming catalyst can include nickel, preferably supported onmagnesia, alumina, silica, zirconia, or magnesium aluminate, singly orin combination, promoted by an alkali metal such as potassium.

Process step B is a cooling step for cooling the synthesis gas streamfrom process step A to a temperature of from about 200° C. to about 600°C., preferably from about 300° C. to about 500° C., and more preferablyfrom about 375° C. to about 425° C., to optimize the temperature of thesynthesis gas effluent for the next step. This cooling may be achievedwith heat sinks, heat pipes or heat exchangers depending upon the designspecifications and the need to recover/recycle the heat content of thegas stream. One illustrative embodiment for step B is the use of a heatexchanger utilizing feed stream F as the coolant circulated through theheat exchanger. The heat exchanger can be of any suitable constructionknown to those with skill in the art including shell and tube, plate,spiral, etc. Alternatively, or in addition thereto, cooling step B maybe accomplished by injecting additional feed components such as fuel,air or water. Water is preferred because of its ability to absorb alarge amount of heat as it is vaporized to steam. The amounts of addedcomponents depend upon the degree of cooling desired and are readilydetermined by those with skill in the art.

Process step C is a purifying step. One of the main impurities of thehydrocarbon stream is sulfur, which is converted by the autothermalreforming process of process step A to hydrogen sulfide. The processingcore used in process step C preferably includes zinc oxide and/or othermaterial capable of absorbing and converting hydrogen sulfide, and mayinclude a support (e.g., monolith, extrudate, pellet etc.).Desulfurization is accomplished by converting the hydrogen sulfide towater in accordance with the following reaction formula III:H₂S+ZnO→H₂O+ZnS  (III)

Other impurities such as chlorides can also be removed. The reaction ispreferably carried out at a temperature of from about 300° C. to about500° C., and more preferably from about 375° C. to about 425° C. Zincoxide is an effective hydrogen sulfide absorbent over a wide range oftemperatures from about 25° C. to about 700° C. and affords greatflexibility for optimizing the sequence of processing steps byappropriate selection of operating temperature.

The effluent stream may then be sent to a mixing step D in which wateris optionally added to the gas stream. The addition of water lowers thetemperature of the reactant stream as it vaporizes and supplies morewater for the water gas shift reaction of process step E (discussedbelow). The water vapor and other effluent stream components are mixedby being passed through a processing core of inert materials such asceramic beads or other similar materials that effectively mix and/orassist in the vaporization of the water. Alternatively, any additionalwater can be introduced with feed, and the mixing step can berepositioned to provide better mixing of the oxidant gas in the COoxidation step G disclosed below.

Process step E is a water gas shift reaction that converts carbonmonoxide to carbon dioxide in accordance with formula IV:H₂O+CO→H₂+CO₂  (IV)

This is an important step because carbon monoxide, in addition to beinghighly toxic to humans, is a poison to fuel cells. The concentration ofcarbon monoxide should preferably be lowered to a level that can betolerated by fuel cells, typically below 50 ppm. Generally, the watergas shift reaction can take place at temperatures of from 150° C. to600° C. depending on the catalyst used. Under such conditions, most ofthe carbon monoxide in the gas stream is converted in this step.

Low temperature shift catalysts operate at a range of from about 150° C.to about 300° C. and include for example, copper oxide, or coppersupported on other transition metal oxides such as zirconia, zincsupported on transition metal oxides or refractory supports such assilica, alumina, zirconia, etc., or a noble metal such as platinum,rhenium, palladium, rhodium or gold on a suitable support such assilica, alumina, zirconia, and the like.

High temperature shift catalysts are preferably operated at temperaturesranging from about 300° C. to about 600° C. and can include transitionmetal oxides such as ferric oxide or chromic oxide, and optionallyincluding a promoter such as copper or iron silicide. Also included, ashigh temperature shift catalysts are supported noble metals such assupported platinum, palladium and/or other platinum group members.

The processing core utilized to carry out this step can include a packedbed of high temperature or low temperature shift catalyst such asdescribed above, or a combination of both high temperature and lowtemperature shift catalysts. The process should be operated at anytemperature suitable for the water gas shift reaction, preferably at atemperature of from 150° C. to about 400° C. depending on the type ofcatalyst used. Optionally, a cooling element such as a cooling coil maybe disposed in the processing core of the shift reactor to lower thereaction temperature within the packed bed of catalyst. Lowertemperatures favor the conversion of carbon monoxide to carbon dioxide.Also, a purification processing step C can be performed between high andlow shift conversions by providing separate steps for high temperatureand low temperature shift with a desulfurization module between the highand low temperature shift steps.

Process step F′ is a cooling step performed in one embodiment by a heatexchanger. The heat exchanger can be of any suitable constructionincluding shell and tube, plate, spiral, etc. Alternatively a heat pipeor other form of heat sink may be utilized. The goal of the heatexchanger is to reduce the temperature of the gas stream to produce aneffluent having a temperature preferably in the range of from about 90°C. to about 150° C.

Oxygen is added to the process in step F′. The oxygen is consumed by thereactions of process step G described below. The oxygen can be in theform of air, enriched air, or substantially pure oxygen. The heatexchanger may by design provide mixing of the air with the hydrogen richgas. Alternatively, the embodiment of process step D may be used toperform the mixing.

Process step G is an oxidation step wherein almost all of the remainingcarbon monoxide in the effluent stream is converted to carbon dioxide.The processing is carried out in the presence of a catalyst for theoxidation of carbon monoxide and may be in any suitable form, such aspellets, spheres, monolith, etc. Oxidation catalysts for carbon monoxideare known and typically include noble metals (e.g., platinum, palladium)and/or transition metals (e.g., iron, chromium, manganese), and/orcompounds of noble or transition metals, particularly oxides. Apreferred oxidation catalyst is platinum on an alumina washcoat. Thewashcoat may be applied to a monolith, extrudate, pellet or othersupport. Additional materials such as cerium or lanthanum may be addedto improve performance. Many other formulations have been cited in theliterature with some practitioners claiming superior performance fromrhodium or alumina catalysts. Ruthenium, palladium, gold, and othermaterials have been cited in the literature as being active for thisuse.

Two reactions occur in process step G: the desired oxidation of carbonmonoxide (formula V) and the undesired oxidation of hydrogen (formulaVI) as follows:CO+½ O₂→CO₂  (V)H₂+½ O₂→H₂O  (VI)

The preferential oxidation of carbon monoxide is favored by lowtemperatures. Since both reactions produce heat it may be advantageousto optionally include a cooling element such as a cooling coil disposedwithin the process. The operating temperature of process is preferablykept in the range of from about 90° C. to to about 150° C. Process stepG preferably reduces the carbon monoxide level to less than 50 ppm,which is a suitable level for use in fuel cells, but one of skill in theart should appreciate that the present invention can be adapted toproduce a hydrogen rich product with of higher and lower levels ofcarbon monoxide.

The effluent exiting the fuel processor is a hydrogen rich gas Pcontaining carbon dioxide and other constituents which may be presentsuch as water, inert components (e.g., nitrogen, argon), residualhydrocarbon, etc. Product gas may be used as the feed for a fuel cell orfor other applications where a hydrogen rich feed stream is desired.Optionally, product gas may be sent on to further processing, forexample, to remove the carbon dioxide, water or other components.

One illustrative embodiment of the present invention is depicted. Fuelprocessor 100 of the present invention contains a series of processunits for carrying out the general process as described in FIG. 1. It isintended that the process units may be used in numerous configurationsas is readily apparent to one skilled in the art. Furthermore, the fuelprocessor described herein is adaptable for use in conjunction with afuel cell such that the hydrogen rich product gas of the fuel processordescribed herein is supplied directly to a fuel cell as a feed stream.

The process equipment described herein may be fabricated from anymaterial capable of withstanding the operating conditions and chemicalenvironment of the reactions described herein and can include, forexample, carbon steel, stainless steel, INCONEL® (a trademark registeredfor use in association with nickel alloys and allows of nickel, chromiumand iron), Incoloy, Hastelloy, and the like. The operating pressure forthe process units are preferably from about 0 to about 100 psig,although higher pressures may be employed. Ultimately, the operatingpressure of the fuel processor depends upon the delivery pressurerequired by the users of the product hydrogen, namely a fuel cell. Forfuel cells operating in the 1 to 20 kW range an operating pressure of 0to about 100 psig is generally sufficient.

Fuel processor 200 as shown in FIG. 2 similar to the processdiagrammatically illustrated in FIG. 1 and described supra. Hydrocarbonfuel feed stream F is introduced to the fuel processor and hydrogen richproduct gas P is drawn off. Fuel processor 200 includes several processunits that each perform a separate operational function and is generallyconfigured as shown in FIG. 2. In this illustrative embodiment, thehydrocarbon fuel feed enters the first compartment 101 into spiralexchanger 201, which preheats the feed against fuel cell tail gas T(enters fuel processor 200 at reactor 214). Because of the multipleexothermic reactions that take place within the fuel processor, one ofskill in the art should appreciate that several other heat integrationopportunities are also plausible in this service. This preheated feedthen enters desulfurization reactor 202 through a concentric diffuserfor near-perfect flow distribution and low pressure drop at the reactorinlet. Reactor 202 contains a desulfurizing catalyst and operates asdescribed in process step C of FIG. 1. Note that this step does notaccord with the order of process steps as presented in FIG. 1. This is aprime example of the liberty that one of skill in the art may exercisein optimizing the process configuration in order to process varioushydrocarbon fuel feeds and/or produce a more pure product. Desulfurizedfuel from reactor 202 is then collected through a concentric diffuserand mixed with air, with the mixture being routed to exchanger 203. Inthis illustrative embodiment, exchanger 203 is a spiral exchanger thatheats this mixed fuel/air stream against fuel cell tail gas T (entersfuel processor 200 at reactor 214).

The preheated fuel/air mixture then enters the second compartment 102,with the preheat temperature maintained or increased by electric coilheater 204 located between the two compartments. The preheated fuel-airmixture enters spiral exchanger 205, which preheats the stream toautothermal reforming reaction temperature against the autothermalreformer 206 effluent stream. Preheated water (enters fuel processor 200at exchanger 212) is mixed with the preheated fuel-air stream prior toentering exchanger 205. The preheated fuel-air-water mixture leavesexchanger 205 through a concentric diffuser and is then fed toautothermal reformer (ATR) 206, which corresponds to process step A ofFIG. 1. The diffuser allows even flow distribution at the ATR 206 inlet.The hot hydrogen product from ATR 206 is collected through a concentricdiffuser and routed back to exchanger 205 for heat recovery. In thisembodiment, exchanger 205 is mounted directly above ATR 206 in order tominimize flow path, thereby reducing energy losses and improving overallenergy efficiency. Flow conditioning vanes can be inserted at elbows inorder to achieve low pressure drop and uniform flow through ATR 206.

The cooled hydrogen product from exchanger 205 is then routed through aconcentric diffuser to desulfurization reactor 207, which corresponds toprocess step C of FIG. 1. The desulfurized product is then fed tocatalytic shift reactor 208, which corresponds with process step E inFIG. 1. Cooling coil 209 is provided to control the exothermic shiftreaction temperature, which improves CO conversion leading to higherefficiency. In this embodiment, cooling coil 209 also preheats ATR 206feed, further improving heat recovery and fuel cell efficiency. Theshift reaction product is then collected through a concentric diffuserand is cooled in spiral exchanger 210, which also preheats water feed W.

Air is then introduced to the cooled shift reaction product, which isthen routed to a concentric diffuser feeding preferred CO oxidationreactor 211. Reactor 211 oxidizes trace CO to CO₂, which corresponds toprocess step G in FIG. 1. Flow conditioning vanes may be inserted atelbows to achieve short flow paths and uniform low pressure dropthroughout reactor 211. The effluent purified hydrogen stream is thencollected in a concentric diffuser and is sent to exchanger 212 whichrecovers heat energy into the water feed W. The cooled hydrogen streamis then flashed in separator 213 to remove excess water WW. The hydrogengas stream P from separator 213 is then suitable for hydrogen users,such as a fuel cell.

In the embodiment described in FIG. 2, the combined anode and cathodevent gas streams from a fuel cell are introduced to fuel processor 200for heat recovery from the unconverted hydrogen in the fuel cell.Integration of the fuel cell with the fuel processor considerablyimproves the overall efficiency of electricity generation from the fuelcell. The fuel cell tail gas T flows through a concentric diffuser toanode tail gas oxidizer (ATO) 214. Hydrogen, and possibly a slip streamof methane and other light hydrocarbons are catalytically oxidizedaccording to:CH₄+2O₂→CO₂+2H₂O  (VII)H₂+½ O₂→H₂O  (VIII)

Equations VII and VIII take place in ATO 214, which can be a fixed bedreactor composed of catalyst pellets on beads, or preferably amonolithic structured catalyst. The hot reactor effluent is collectedthrough a concentric diffuser and is routed to exchanger 203 for heatrecovery with the combined fuel/air mixture from reactor 202. Heat fromthe fuel cell tail gas stream T is then further recovered in exchanger201 before being being flashed in separator 215. The separated water isconnected to the processor effluent water stream WW and the vent gas isthen vented to the atmosphere.

Such a skilled person in the art should also appreciate that the presentinvention also encompasses the following illustrative embodiments. Onesuch illustrative embodiment is an apparatus for converting hydrocarbonfuel into a hydrogen rich gas, comprising a manifold for mixing thehydrocarbon fuel with an oxygen-containing gas to give a fuel mixture,an autothermal reactor including a catalyst for reacting the fuelmixture under autothermal reforming conditions to give a hydrogencontaining gaseous mixture, a water gas shift reactor including acatalyst for reacting the hydrogen containing gaseous mixture underwater gas shift reaction conditions to give an intermediate hydrogencontaining gaseous mixture with a substantially reduced carbon monoxidecontent, and a selective oxidation reactor including a catalyst forreacting the intermediate hydrogen containing gaseous mixture underselective oxidation reaction conditions to produce the hydrogen richgas. A preferred aspect of this embodiment includes a heat exchanger forheating the hydrocarbon fuel prior to feeding the hydrocarbon fuel feedto the manifold. Another preferred aspect of this embodiment is adesulfurization reactor including a catalyst for reacting the heatedhydrocarbon fuel under desulfurization conditions to produce asubstantially desulfurized hydrocarbon fuel feed to the manifold. Yetanother preferred aspect of this embodiment includes a heat exchangerfor heating the fuel mixture prior to feeding the autothermal reactor.Yet another preferred aspect of this embodiment includes anotherdesulfurization reactor including a catalyst for reacting the hydrogencontaining gaseous mixture under desulfurization conditions to produce asubstantially desulfurized hydrogen containing gaseous mixture feed tothe water gas shift reactor. Yet another preferred aspect of thisembodiment is all anode tail gas oxidizer including a catalyst forreacting the unconverted hydrogen from a fuel cell under oxidationconditions to create a hot anode tail gas oxidizer effluent. This hotanode tail gas oxidizer effluent can be used to heat integrate with theprocess and improve the overall energy efficiency of the apparatus.

Another illustrative embodiment is an apparatus for convertinghydrocarbon fuel into a hydrogen rich gas, comprising a first heatexchanger for heating the hydrocarbon fuel to produce a heatedhydrocarbon fuel, a first desulfurization reactor for reacting theheated hydrocarbon fuel to produce a substantially desulfurizedhydrocarbon fuel, a manifold for mixing the substantially, desulfurizedhydrocarbon fuel with an oxygen containing gas to produce a fuelmixture, a second heat exchanger for heating the fuel mixture to producea heated fuel mixture, an autothermal reactor including a catalyst forreacting the heated fuel mixture to produce a first hydrogen containinggaseous mixture, a second desulfurization reactor for reacting the firsthydrogen containing gaseous mixture to produce a second hydrogencontaining gaseous mixture that is substantially desulfurized, a watergas shift reactor for reacting the second hydrogen containing gaseousmixture to produce a third hydrogen containing gaseous mixture with asubstantially decreased carbon monoxide content, and a selectiveoxidation reactor for reacting the third hydrogen containing gaseousmixture to produce the hydrogen rich gas. Yet another preferred aspectof this embodiment is an anode tail gas oxidizer including a catalystfor reacting the unconverted hydrogen from a fuel cell under oxidationconditions to create a hot anode tail gas oxidizer effluent. This hotanode tail gas oxidizer effluent can be used to heat integrate with theprocess and improve the overall energy efficiency of the apparatus.

Yet another illustrative embodiment of the present invention is aprocess for converting hydrocarbon fuel into a hydrogen rich gas bymixing the hydrocarbon fuel with an oxygen containing gas to produce afuel mixture, then reacting the fuel mixture in the presence of acatalyst under autothermal reforming reaction conditions to produce ahydrogen containing gaseous mixture, then reacting the hydrogencontaining gaseous mixture in the presence of a catalyst under water gasshift reaction conditions to produce an intermediate hydrogen containinggaseous mixture with a substantially reduced carbon monoxide content,and then reacting the intermediate hydrogen containing gaseous mixturein the presence of a catalyst under selective oxidation conditions toproduce the hydrogen rich gas. A preferred aspect of this embodimentincludes heating the hydrocarbon fuel before the mixing step. Anotherpreferred aspect of this embodiment is reacting the heated hydrocarbonfuel in the presence of a catalyst under desulfurization conditions tosubstantially desulfurize the hydrocarbon fuel prior to the mixing step.Yet another preferred aspect of this embodiment includes heating thefuel mixture prior to the first reaction step. Another preferred aspectof this embodiment includes reacting the hydrogen containing gaseousmixture in the presence of a catalyst under desulfurization reactionconditions to substantially desulfurize the hydrogen containing gaseousmixture prior to the second reaction step. It is intended that thisembodiment be able to reduce the carbon monoxide concentration in thehydrogen rich gas to less than 50 ppm. Yet another preferred aspect ofthis embodiment is utilizing an anode tail gas oxidizer including acatalyst for reacting the unconverted hydrogen from a fuel cell underoxidation conditions to create a hot anode tail gas oxidizer effluent.This hot anode tail gas oxidizer effluent can be used to heat integratewith the process and improve the overall energy efficiency of theapparatus.

Yet another illustrative embodiment of the present invention is a methodfor converting hydrocarbon fuel into a hydrogen rich gas by heating thehydrocarbon fuel to produce a heated hydrocarbon fuel, then reacting theheated hydrocarbon fuel in the presence of a catalyst underdesulfurization conditions to produce a substantially desulfurizedhydrocarbon, then mixing the substantially desulfurized hydrocarbon withan oxygen containing gas to produce a fuel mixture, then heating thefuel mixture to produce a heated fuel mixture, then reacting the heatedfuel mixture in the presence of a catalyst under auto thermal reformingconditions to produce a first hydrogen containing gaseous mixture, thenreacting the first hydrogen containing gaseous mixture in the presenceof a catalyst under desulfurization conditions to produce a secondhydrogen containing gaseous mixture that is substantially desulfurized,then reacting the second hydrogen containing gaseous mixture with acatalyst under water gas shift reaction conditions to produce a thirdhydrogen containing gaseous mixture with a substantially reduced carbonmonoxide content, and then reacting the third hydrogen containinggaseous mixture in the presence of a catalyst under selective oxidationreaction conditions of to produce the hydrogen rich gas. It is intendedthat this embodiment be able to reduce the carbon monoxide concentrationin the hydrogen rich gas to less than 50 ppm. Yet another preferredaspect of this embodiment is utilizing an anode tail gas oxidizerincluding a catalyst for reacting the unconverted hydrogen from a fuelcell under oxidation conditions to create a hot anode tail gas oxidizereffluent. This hot anode tail gas oxidizer effluent can be used to heatintegrate with the process and improve the overall energy efficiency ofthe apparatus.

While the apparatus and methods of this invention have been described interms of preferred embodiments, it will be apparent to those of skill inthe art that variations may be applied to the process described hereinwithout departing from the concept and scope of the invention. All suchsimilar substitutes and modifications apparent to those skilled in theart are deemed to be within the scope and concept of the invention.

1. A method for converting hydrocarbon fuel into a hydrogen rich gas,comprising: mixing the hydrocarbon fuel with an oxygen containing gas toproduce a fuel mixture; reacting the fuel mixture in the presence of acatalyst under autothermal reforming reaction conditions to produce ahydrogen containing gaseous mixture; reacting the hydrogen containinggaseous mixture in the presence of a catalyst under water gas shiftreaction conditions to produce an intermediate hydrogen containinggaseous mixture with a substantially reduced carbon monoxide content;and reacting the intermediate hydrogen containing gaseous mixture in thepresence of a catalyst under selective oxidation conditions to producethe hydrogen rich gas.
 2. The method according to claim 1, furthercomprising heating the hydrocarbon fuel to produce a heated hydrocarbonfuel, wherein the heated hydrocarbon fuel becomes the hydrocarbon fuelfeed to the mixing step.
 3. The method according to claim 2, furthercomprising reacting the heated hydrocarbon fuel in the presence of acatalyst under desulfurization conditions to produce a substantiallydesulfurized hydrocarbon fuel, wherein the substantially desulfurizedhydrocarbon fuel becomes the hydrocarbon fuel feed to the mixing step ina manifold.
 4. The method according to claim 1, further comprisingheating the fuel mixture to produce a heated fuel mixture, wherein theheated fuel mixture becomes the fuel mixture feed to the first reactionstep.
 5. The method according to claim 1, further comprising reactingthe hydrogen containing gaseous mixture in the presence of a catalystunder desulfurization reaction conditions to produce a substantiallydesulfurized hydrogen containing gaseous mixture, wherein thesubstantially desulfurized hydrogen containing gaseous mixture becomesthe hydrogen containing gaseous mixture feed to the second reactionstep.
 6. The method according to claim 1, wherein the hydrocarbon fuelis selected from the group consisting of natural gas, methane, ethane,propane, butane, liquefied petroleum gas, naphtha, gasoline, kerosene,diesel, methanol, ethanol, propanol, and combinations thereof.
 7. Themethod according to claim 1, wherein the hydrogen rich gas contains lessthan 50 ppm of carbon monoxide.
 8. The method according to claim 1,further comprising reacting anode tail gas from a fuel cell in thepresence of a catalyst under oxidation conditions to produce a hot anodetail gas oxidizer effluent.
 9. The method according to claim 8, whereinthe hot anode tail gas oxidizer effluent preheats the hydrocarbon fuel.10. A method for converting hydrocarbon fuel into a hydrogen rich gas,comprising heating the hydrocarbon fuel to produce a heated hydrocarbonfuel; reacting the heated hydrocarbon fuel in the presence of a catalystunder desulfurization conditions to produce a substantially desulfurizedhydrocarbon; mixing the substantially desulfurized hydrocarbon with anoxygen containing gas to produce a fuel mixture; heating the fuelmixture to produce a heated fuel mixture; reacting the heated fuelmixture in the presence of a catalyst under auto thermal reformingconditions to produce a first hydrogen containing gaseous mixture;reacting the first hydrogen containing gaseous mixture in the presenceof a catalyst under desulfurization conditions to produce a secondhydrogen containing gaseous mixture that is substantially desulfurized;reacting the second hydrogen containing gaseous mixture with a catalystunder water gas shift reaction conditions to produce a third hydrogencontaining gaseous mixture with a substantially reduced carbon monoxidecontent; and reacting the third hydrogen containing gaseous mixture inthe presence of a catalyst under selective oxidation reaction conditionsof to produce the hydrogen rich gas.
 11. The method according to claim10, wherein the hydrocarbon fuel is selected from the group consistingof natural gas, methane, ethane, propane butane, liquefied petroleumgas, naphtha, gasoline, kerosene, diesel, methanol, ethanol, propanol,and combinations thereof.
 12. The method according to claim 10, whereinthe hydrogen rich gas contains less than 50 ppm of carbon monoxide. 13.The method according to claim 10, further comprising reacting anode tailgas from a fuel cell in the presence of a catalyst under oxidationconditions to produce a hot anode tail gas oxidizer effluent.
 14. Themethod according to claim 13, wherein the hot anode tail gas oxidizereffluent preheats the hydrocarbon fuel.